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Abstract:
In this seminar, we explore signatures of dynamical quantum phase transitions (DQPTs) induced by quantum quenches in a correlated quantum dot coupled to superconducting and metallic leads. In equilibrium, proximity-induced electron pairing competes with Coulomb repulsion, driving the dot into either a spin-doublet or a BCS-like singlet ground state.
We study the real-time dynamics across this phase boundary using the time-dependent numerical renormalization group (tdNRG), formulated in the matrix product state language. Analyzing the Loschmidt echo, we find nonanalyticities in its rate function that signal DQPTs, accompanied by local extrema in the dot's pairing correlations and occupation. Finally, we extend the analysis to a ferromagnetic metallic lead, which induces an effective exchange field on the dot. The resulting time-dependent local magnetization could be probed with spin-sensitive detection techniques.
We study the real-time dynamics across this phase boundary using the time-dependent numerical renormalization group (tdNRG), formulated in the matrix product state language. Analyzing the Loschmidt echo, we find nonanalyticities in its rate function that signal DQPTs, accompanied by local extrema in the dot's pairing correlations and occupation. Finally, we extend the analysis to a ferromagnetic metallic lead, which induces an effective exchange field on the dot. The resulting time-dependent local magnetization could be probed with spin-sensitive detection techniques.
The seminar is organized by Department of condensed matter theory